1. Field of the Invention
This invention relates to an anchoring system for cavity walls having an outer wythe of rubble stone. More particularly, the invention relates to an anchoring system that adjusts to the irregular surface structure and uneven nature of irregular rubble stone courses.
2. Description of the Prior Art
Masonry is a highly durable form of construction. However, the materials used, the quality of the mortar and workmanship, and the pattern utilized in the assembly of the units strongly affect the aesthetics and durability of the overall masonry construct. The appearance of a rubble stone outer wythe imparts an impression of solidity and permanence, adding to the aesthetic value of a building. The use of rubble stone increases the thermal mass of a building, giving increased comfort in the heat of summer and the cold of winter.
Common rubble stone walls have been built since the beginning of ancient civilizations. Early rubble stone walls were constructed by the first builders and likely the Egyptians built rubble stone walls from the pieces left over from forming the giant pyramid stones. Because rubble stones are rough and irregular fragments of broken stone formed by a geological or quarrying process, they are plentiful and considered to be a common stone. Rubble stones are generally less expensive than hand formed, split or cut stone. Rubble stone is aesthetically pleasing especially when a rough, earthy appearance is desired. Some common uses for rubble stone are retaining walls, garden walls, house walls, landscaping and fireplaces.
Among the American architectural uses of rubble stone walls is that of the use of rubble stone building exteriors of the Arts and Crafts movement. This is seen especially in the work of the Greene brothers in Pasadena, Calif. in the early 1900's. As the popularity of rubble stone exteriors in commercial buildings grows, building code compliant methods of anchoring the rubble stones to an inner wythe are needed. The present invention solves the technical issues relating to rubble stone outer wythes, through a novel anchoring system that limits veneer tie lateral movement and front-to-back displacement.
While rubble stone outer wythes exert extraordinary compressive strength (vertical loads) the tensile strength (twisting or stretching) thereof needs the enhancement of a well-designed anchoring and reinforcement system. Typically the anchoring system spans the cavity between the rubble stone veneer, tying the veneer to the structural inner wythe generally composed of concrete masonry units, steel columns or poured concrete. Most insulated buildings that utilize cavity wall construction feature insulation set within the cavity, as well as a drainage system.
Rubble stone used in masonry veneer are either “dressed” or “rough.” Stone masonry utilizing dressed stones is known as ashlar masonry, whereas masonry using irregularly shaped stones is known as rubble masonry. Both rubble and ashlar masonry can be laid in courses (rows of even height) through the careful selection or cutting of stones. However, most rubble stone masonry is uncoursed and rough with unhewn building stone set in mortar, but not laid in regular courses.
When specific masonry veneers face high lateral loads, such as wind and seismic forces. The masonry veneer must be “tied” back to a structural inner wythe so as to carry the imposed loads. The masonry veneer must be continuously supported at regular vertical and horizontal intervals with masonry anchors because without continuous support, the masonry veneer may become over stressed, leading to vertical cracking and possible fracture. To address these issues, outer wythe wire reinforcements and tie backs are incorporated into the irregular mortar joints of the outer wythe to reinforce, bond and control shrinkage cracking.
The uneven nature of uncoursed rubble stone outer wythes presents a unique set of difficulties with regard to reinforcement and tie backs. The wire reinforcements and anchors that do not provide a high degree of adjustability to conform to the uneven nature of the rubble stone are not effective in securing a rubble stone outer wythe. Vertically adjustable ties with limited lateral movement and front-to-back displacement are required to address the problem of when the rubble stone mortar joints do not align with the inner wythe anchors.
In the past, anchoring random or rubble stone walls generally involved some form of penetration of the individual stones with an anchor. Such prior art is described in U.S. Pat. No. 6,719,487—Yukimoto et al.—Issued Apr. 13, 2004, entitled “Structural Unit for Construction, Construction of Said Structural Units, and Method for the Preparation of Said Structural Units and Said Construction,” which describes an anchor for the construction of a revetment, retaining wall or the like, and U.S. Pat. No. 4,765,112—Lafayette, Jr.—Issued Aug. 23, 1988, entitled “Apparatus and Method for Mounting Stone Siding,” which describes a mounting system for natural stone curtain walls. The individual penetration of the stone is time consuming and labor and materials intensive.
Further advancements in the prior art concern the use of masonry rubble or random stone walls as the outer wythe of a cavity wall structure. Such advancement resulted in the development of the Dur-O-Wall Random Rubble/Stone System that utilizes a combination of three parts, truss or ladder reinforcements with welded triangular tabs, J-bars, and triangular ties. The Dur-O-Wall disclosure requires a large cavity space to house the ties and does not restrict veneer tie lateral movement or front-to-back displacement. Another variation of a rubble masonry veneer support system is Fero Corporation's system that employs an anchor with a longitudinally extended slotted extension for use with a flanged tie. The Fero system does not provide full vertical adjustability and requires a large anchoring unit. The present invention addresses the shortcomings of the Fero and Dur-O-Wall devices. The present invention limits veneer tie lateral movement and front-to-back displacement. Additionally, the Hohmann anchoring system requires less materials and labor to install, saving both time and costs.
The present inventor developed several variations of an anchor system for rubble stone outer wythes that are for use with masonry block, steel column and poured concrete inner wythes. The novel inventions include vertical hooks or J-hooks connected to surface mounted anchors or anchor extensions of ladder and truss joint reinforcements. The veneer tie is secured to the vertical hook or J-hook for insertion in the outer wythe. The veneer tie is either a flexible buckle tie or a triangular shaped tie surrounding the vertical hook or J-hook. The present invention improves on the prior art Hohmann system through the use of a novel tie that lessens the required width of the cavity and controls lateral movement and front-to-back displacement.
The inventors' patents and their assignee's product line include masonry accessories, namely, ladder and truss reinforcements, wall anchors, veneer ties, masonry flashing and related items for cavity walls. These products, which are sold under the trademarks of Lox All, DW-10×, X-seal and FlexFlash, are manufactured by Hohmann & Barnard, Inc., Hauppauge, N.Y. 11788 (“H&B”), a unit of MiTek Industries, Inc., a Berkshire Hathaway subsidiary. The products have become widely accepted in the construction industry and the inventors have gained particular insight into the technological needs of this marketplace.
In the past, the anchoring systems for rubble stone outer wythes did not fully address the uneven nature of the uncoursed rubble stone. The present invention solves the anchoring problem related to the use of a rubble stone outer wythe by providing an anchoring system that allows vertical adjustability without significant lateral movement or front-to-back displacement. The present invention further allows for a smaller cavity to house the veneer tie.
n preparing for this application the following patents and patent applications came to the attention of the inventors and are believed to be relevant to the further discussion of the prior art:
Pat.InventorIssue Date7,469,511WobberDec. 30, 20086,351,922Burns, et al.Mar. 5, 20024,596,102Catani, et al.Jun. 24, 19864,373,314AllanFeb. 15, 1983
U.S. Pat. No. 7,469,511—Wobber—Issued Dec. 30, 2008 discloses a masonry coupling system that employs a longitudinally extended anchor having a channel body that interfaces with a key. The key is secured within the outer wythe and is vertically adjustable. The Wobber device is for use with a uniform outer wythe.
U.S. Pat. No. 6,351,922—Burns et al. —Issued Mar. 5, 2002 describes an adjustable wall tie for a cavity wall that includes a J-shaped single-ended hook that is vertically adjusted. The single-end hook is used either side up so that vertical adjustment is extended. The Burns device is for use with a coursed outer wythe.
U.S. Pat. No. 4,596,102 Catani et al.—Issued Jun. 24, 1986 discloses a cavity wall anchor and tie. The anchor comprises a channel with a slotted web for receiving a veneer tie. The anchor is adjustable translationally and pivotally as a unit, expanding the vertical adjustment capability of the tie. The adjustability of the tie is limited to the distance between the screw and the slotted web.
U.S. Pat. No. 4,373,314—Allan—Issued Feb. 15, 1983 discloses an anchor assembly having an outstanding leg with slotted holes formed therein for interconnection with a veneer tie. The veneer tie is vertically adjustable within the slotted holes. The limits of adjustability are prescribed by the ends of the two slots.
None of the above references provide the advancements in anchoring systems for cavity walls with a rubble stone outer wythe set forth herein. The present novel invention offers a multi-purpose solution by resolving issues relating to lateral loads, uneven outer wythe bed joints and vertical adjustability without significant lateral movement or front-to-back displacement. Through the use of the present novel anchoring system for rubble stone outer wythe, code requirements are met and construction costs are reduced.
The present invention provides an advancement in rubble stone reinforcement and anchoring technology by providing an anchoring system for irregular surface outer wythes that provides the same stability as an anchoring system for standard bed joints. The present anchoring system resolves past problems relating to vertical adjustability, increased cavity size, lateral movement and front-to-back displacement, while simultaneously reducing installation labor and energy costs, thereby saving time and money.
As will become clear in reviewing the disclosure which follows, the rubble stone anchoring system benefits from the recent developments described herein that leads to solving the problems of constructing an aesthetically pleasing commercial structure efficiently, from both a structural as well as a cost/time perspective.